Gas turbine engine combustion chambers experience extremely high temperatures in operation and the walls of the combustion chambers are generally cooled using a coolant.
It is known to provide a combustion chamber comprising an inner wall and an outer wall and the inner wall of the combustion chamber comprising segments, or tiles, and in particular the inner wall comprises a plurality of segments, or tiles, supported on the outer wall. The tiles consist of high temperature resistant material, e.g. a nickel base superalloy. The tiles are spaced from the inner surface of the outer wall to provide a passage for coolant. The outer wall of the combustion chamber may have apertures extending there-through to provide impingement cooling of the outer surfaces of the tiles. The tiles may have pedestals projecting from their outer surfaces to provide convection cooling of the tiles. The tiles may have apertures extending there-through to provide film cooling, or effusion cooling, of the inner surfaces of the tiles. The tiles may have a thermal barrier coating on their inner surface to provide further protection for the inner surfaces of the tiles.
Each tile is generally mounted on the outer wall using studs which are integral with the tile and which extend through mounting apertures in the outer wall. The studs are generally threaded and washers and nuts are fastened onto the studs.
Our U.S. Pat. No. 5,435,139 discloses an outer wall of a combustion chamber with apertures extending there-through to provide impingement cooling of the outer surfaces of the tiles and apertures extending through the tiles to provide film cooling, or effusion cooling, of the inner surfaces of the tiles. U.S. Pat. No. 5,435,139 uses threaded studs and nuts to mount the tiles on the outer wall.
Our U.S. Pat. No. 6,857,275 discloses an outer wall of a combustion chamber with apertures extending there-through to provide impingement cooling of the outer surfaces of the tiles, pedestals projecting from the outer surfaces of the tiles to provide convection cooling of the tiles and apertures extending through the tiles to provide film cooling, or effusion cooling, of the inner surfaces of the tiles. U.S. Pat. No. 6,857,275 uses threaded studs and nuts to mount the tiles on the outer wall.
The outer wall of the combustion chamber is generally manufactured as an annular outer wall. One conventional method of manufacturing an annular outer wall comprises forging a metal billet into a forged ring, turning the forged ring and then drilling apertures through the forged ring. Another conventional method of manufacturing an outer annular wall comprises forming sheet metal pieces, welding the pieces together to form a ring and then drilling apertures through the fabricated ring.
The inner wall of the combustion chamber is generally manufactured by casting the tiles, drilling apertures through the tiles and then coating the inner surfaces of the tiles with a thermal barrier coating.
Finally the tiles of the inner wall are assembled onto the outer wall by inserting the studs on the tiles through cooperating mounting apertures in the outer wall and then placing washers and nuts on each of the studs.
Thus, the method of manufacturing each wall of a combustion chamber is complicated and requires a number of manufacturing processes, e.g. casting, drilling and depositing a coating for a tile of the inner wall or forging, turning and drilling of the outer wall.
The present invention seeks to provide a novel method of manufacturing a wall of a combustion chamber which reduces, preferably overcomes, the above-mentioned problem.